The articles below will be published online November 30, 2006 at 4 p.m. (EST) by the American Journal of Public Health under "First Look" at ajph/first_look.shtml, and will appear in the January 2007 print issue of the Journal. "First Look" articles have undergone peer review, copyediting and approval by authors but have not yet been printed to paper or posted online by issue. The American Journal of Public Health is published by the American Public Health Association, apha, and is available at ajph.

1) DECLINES IN TEEN PREGNANCY TIED TO ABSTINENCE OR CONTRACEPTION?

The dramatic, recent declines in teen pregnancy rates in the United States are primarily the result of improved use of contraceptives among teenagers.

Teen pregnancy rates in the United States have declined remarkably since 1990, according to a new study from Columbia University and Guttmacher Institute. Columbia and Guttmacher investigators examined sexual behavior and contraceptive use among young women ages 15-19 to determine the contributions of abstinence and contraceptive use to the decline in teen pregnancy. They found that 86 percent of the decline in pregnancy risk was linked to improved use of contraception, with increasing use of birth control pills and condoms and an increased use of two methods at last sex (for example, pills and condoms). Reduced sexual activity explained 14 percent of the decline in teen pregnancy. Using data from the National Survey of Family Growth for 1995 and 2002, the study's authors developed a "Contraceptive Risk Index" that summarized the effectiveness of teen contraceptive use, based on prevalence of non-use and use of each method and published contraceptive failure rates. Researchers also developed an "Overall Pregnancy Risk Index" based upon the contraceptive risk score and the percentage of teens reporting sexual activity. Among younger teens (15-17 years old), 77 percent of pregnancy decline was attributable to improved contraceptive use and 23 percent to reduced sexual activity.

[From: "Explaining Recent Declines in Adolescent Pregnancy in the United States: the Contribution of Abstinence and Improved Contraceptive Use" ]

2) MOMS' OBESITY UPS RISK OF PRETERM BIRTH

Obese first-time moms are at an increased risk for preterm birth because they are more likely to have complications, such as high blood pressure, that make their doctor choose to deliver the baby before full term.

Researchers studied 187,290 women in Scotland and analyzed their body mass index (BMI) to determine categories of overweight, obese and morbidly obese mothers. For first-time moms, being morbidly obese, with a BMI of 35 or greater, increased the overall risk of preterm birth. This led to threefold increased risks of a neonatal death and delivering an extremely low birth weight baby (